This invention, in general, relates to steering systems as applied to small pleasure boats, particularly to outboard engines and inboard/outdrive units.
The majority of small boats use some form of cable steering system. Boats with engines of around 25 horsepower use a continuous small diameter cable. Each end of the cable is affixed to the two sides of the engine, the center of the cable being wrapped around a steering wheel capstan. There are two major problems with this system, the least severe problem being the slippage between cable and capstan. The biggest problem is one of corrosion and subsequent breakage of constantly weather exposed cables.
Larger horsepower engines of up to 125 HP use a cable system known as the "Morse" system. This system uses a much heavier cable enclosed in a flexible housing. The housing reduces corrosion and the heavier cable almost eliminates breakage, but the problem now becomes one of routing the stiffer cable within the narrow confines of the boat. The single cable and its housing have to make some very sharp bends for a cable of this size, resulting in increased wear at these points. As stated previously, this housing reduces corrosion but does not eliminate it. This corrosion and wear of the friction reducing lining continue until the cabe refuses to slide in its housing. The only cure now will be an expensive replacement of the cable.
An additional problem of the single cable system is that the cable has to push the engine about its steering axis, as well as pull. Bending of the cable in its push mode has not been a problem with the torque of engines below 125 HP. Larger engines have created bending of the cables. The boat industries solution to date has been to add an additional cable to the same side of the engine. The two cables still must push the motor, a job that a cable is not very well suited for. These cables are very expensive and we now have a double expense without doing anything for corrosion and rapid wear.
A hydraulic system would result in a positive means of steering the boat and corrosion would be drastically reduced. Flexible hydraulic lines could be routed wherever the boat manufacturer desired without having to consider any binding problems. The system could be similar to that used in the automobile industry where an inboard engine was utilized, and would even be possible with an outboard engine, but either system would be needlessly expensive in the small pleasure boats.
A much simpler system would consist of one hydraulic cylinder driving another hydraulic cylinder.